Automatic compensating chuck



Feb. 15, 1927. 17,403

J. E. LOVELY AUTOMATI C COMPENSATING CHUCK Filed March 1 1924 7Sheets-Sheet 1 IZ ZZUQ/ZYW (757272 Ji'fiaver J. E. LOVELY AUTOMATICCOMPENSATING CHUCK Feb. 15, 1927.

Filed March 1924 7 Sheets-Sheet 2 Feb. 15 l 927 J. E. LOVELY AUTOMATICCOMPENSATING cnucx 7 Sheets-Sheet 5 1560a '71' (70%;? Z law? Feb. 15,1927.

J. E. LOVELY AUTOMATIC COMPENSATING CHUCK Sheets-Sheet 4 Mew & Jku Z.liafleg m q m Filed March 1 1 617,403 Feb. 15, 1927. J E LOVELY vAUTOMATIC COMPENSATING CHUCK Filed March 1924 '7 Sit et-Shee'lf. 5

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Feb. 15 192 7 J. E. LOVELY AUTOMATIC COMPENSATING CHUCK 1924 7Sheets-Sheet 6 Filed March 1,

Feb. 15, 1927. 1,617,403

J. E. LOVELY AUTOMATIC COMPENSATING CHUCK Filed March 1924 Sheets -Sheet'7 L757? Illa Patented Feb. 15, 1927.

arena ear in ear JOHN E. LOVELY, F SPRINGFIELD, VERMONT, ASSIGNOB TOJONES 80 LAWSON MA- CHINE COMPANY, OF SPRINGFIELD, VEBIVION'L, ACORPORATION OF VERMONT.

AUTOMATIC COMPENSATING CHUCK.

Application filed March 1, 1924. Serial No. 696,381.

This invention relates to chucks designed for supporting irregularforms, more particularly crank and cam shafts and the like, correctlycentered with relation to their bearings so that these bearings may beturned and faced. Chucks as heretofore designed for this purpose havecommonly been provided with set screws arranged to bear on the work atspaced points and ithas been necessary to carefully bring up each screwindividually to properly center thework and then to tighten themindividually, turning the work over by hand so that each screw in turnmay be rendered accessible for both bringing up and tightening.Considerable time is thus required to set up the work before machiningcan be commenced.

According to the present invention a floating clamp automaticallyadapting itself to the configuration of the work is employed, this clampafter it has properly engaged the work being fixed by a single fasteneragainst further floating relative to the axis of rotation of the chuck.Thus but two clamping actions, each of a very simple and easily effectednature, are necessary to properly'secure the work for the machiningoperations.

Work such as gas engine cam shafts and long slender pieces it hasheretofore been necessary to turn or spot intermediate its ends and thento use a steady rest bearing on the spotted portion.

The present invention eliminates the necesthe steady rest.

For a more complete understanding of this invention reference may he hadto the ac companying drawings in which- Figure 1 is a fragmentaryelevation of a lathe of the well known Fay type showing a compensatingchuck particularly designed to support engine crank shafts in order toturn their bearings.

Figure 2 is an elevation of the crank shaft. Figure 3 is a perspectiveof a portion of the lathe looking down on the work toward the headstockend.

Figures 4 and 5 are perspectives of the work clamping jaws. I

Figure 6 is a section on line 6-6 of Figure 1.

Figure 7 is a fragmentary rear elevation of the parts shown in Figure 6.

sity of the spotting operation and the use of F gures 8, 9, 10 and 11are detail sections on llnes 88, 99, 10l0 and 11-11, respectively, ofFigure 6, Figurefi also represent ng a section on line 88 of Figure 11.

F gure 12 is a perspective of a gage block.

Figures 13 and 14 are elevations of this block looking from oppositesides.

Figure 15 is a detail plan showing the gage block in position relativeto the work and to theface of the chuck.

Figure 16 is a section somewhat similar to Figure 11 but shown inconnection with a modified form of chuck particularly designed forholding gas engine cam shafts. The cam shaft is also shown in relationto certain of the machining tools.

Figures 17 and 18 are perspectives of the clamping jaws for the chuckillustrated in Figure 16. Y

Figure 19 is a section on line 1919 of Figure 16.

Figure 20 is a section on line 2020 of Figure 19.

Figure 21 is an elevation of the support for the clamping jaws.

Figure 22 is a section similar to Figure 19 but showing a modification.

Figures 23 and 24 are sections on lines 23-9. and 24-2-1 of Figure 22.

Figures 25 and 26 are plans of the clamping jaws of Figure 22 looking inopposite directions.

. Figure 27 is a View similar to Figure 21 but showing the modificationof Figure 22.

Figure 28 is a perspective showing a further modification of one of theclamping aws.

Referring first to Figure 11 at 1 is indicated a support or drum adaptedto be fixed at one end 2 to the end of the machine spindle 3. As shownthe drum has a central externally threaded hub or boss 3 thereon havinga slot 4 therein for the reception of a. key 5 fixed to the end of thespindle 3, the spindle terminating in an annular shoulder 6 againstwhich may engage the inwardly turned flange 7 of a collar 8 havinc:internal threads 9 engaging the threads of the boss or hub 53 by whichmeans the drum may be clamped to the end of the spindle to rotatetherewith. Within the spindle is carried a machine center 10 which isshown as mounted with capability of axial movement, being pressedoutwardly from the-end of the spindle as far as permitted by the end ofa screw plug 11 'riding in a slot 12 therein by means of a spring 13seated in a socket 14 axially of the spindle and reacting against theend of a pin 15 having a head 16 threaded in a sleeve 17.- The sleeve17' also slidably receives the center 10 at its outer end and at itsinner end it has fixed therein the forward end of a rod 18. This rod 18forms part of the standard centering mechanism of a Fay lathe. Thesleeve 17 has enlarged forward portions 20 fitted within a bore 21 inthe end wall of the support or drum 1, and mounted in a longitudinalperforation 22 therein is a rod 23 engaged at its outer end by athreaded adjusting plug 24. The inner end of the rod 23 bears againstthe outer end of an externally tapered sleeve 25 riding in theinternally tapered bore 26 of the spindle 3. This sleeve 25 at itsouter-end passes within the bore through the end of the drum 1 andserves to center it accurately with relation to the axis of rotation ofthe spindle.

The drum 1 is hollow and may receive work through an opening 30 in itsopposite end. the work being herein shown as a crank shaft 310, one endof which may bearagainst the center 10. This outer end of the drum orsupport is designed to carry work-clamping mechanism which may adaptitself to the configuration of the work to be held and then be clampedto the drum to rotate therewith. This mechanism is so designed that itmay engage the rough forging directly without requiring any preliminaryspotting or turning. It comprises a clamping member or jaw 31 showndetached in Figure 5 and a mating clamping jaw 32 shown detached inFigure 4. The jaw 31 at one end has a pair of spaced ears 33 betweenwhich is pivoted a lug 34 projecting from the member 32 there beingmating perforations and 36 in these parts through which passes a pivotpin 37 (see Figures 6, 7 and 9). This pivot may be fixed in position bymeans of a plug 38 threaded in a perforation 39 in the lug 34, the innerend of this plug engaging a depression in the pin 37. A lock plug 40 maybe threaded in the socket 39 and bear against the outer end of the plug38.

The work-clamping member 31 has a transverse keyway in its rear face andslidable in this keyway is a key 46. This key is provided with aperforation through which extends with a close fit a pivot bolt 48. Thisbolt also extends with a close fit through a perforation 49 in the endwall of the drum and with a loose fit through a perforation 50 throughthe member 31. This perforation 50 is counterbored at its outer end at51 to loosely receive the head 52 of the bolt 48 and the opposite end ofthis bolt has threaded thereon a pair of nuts 53 by which it may befixed in position. \Vith this construction the member 31 may be movedalong with the key 46 across the endv face of the drum and it may alsopivot about the in 48. It is not, however, permitted any odily movementlaterally of the length of the. key. In the position of the chuck whenit is stationary for the insertion or removal of work, this key 46extends substantially horizontally so that the member 31 is permitted aroking movement and a bodily horizontal movement, but no bodily verticalmovement, this construction furnishing a floating connection between themember 31 and the drum. As the jaw 32 is carried by the member 31, italso is capable of a floating movement relative to the end face of thedrum with the member 31.

Means are provided for clamping the jaw 32 to the member 31 to fix thework rigidly therebetween. This may comprise, as shown best in Figures 3and 6, a bolt pivoted at 61 between jaws 62 of the member 31 and havingthreaded on its outer end a nut 63 engageable with the upper faces of apair of jaws 64 between which the bolt 60 may be moved. One or both ofthese clampingn'iembers 31 and 32 may be provided with removable wearpieces 65 engaging the work.

Due to the floating movement of this clamping mechanism comprising theclamping jaws, this mechanism may conform to the position of the workplaced between the center 10 and a dead center ofthe machine so that thework may find its own center relating to the chuck. If then thismechanism is clamped in this position to the drum it will therefore beproperly held in this centered relation for the machining operations.Means for holding this mechanism in. position may consist of a clampingrod slidable axially with a tight fit through the drum 1 and havin ahead 71 at its outer h end which may be brought against the outer faceof the clamping mechanism and hold it tightly against the end of thedrum.

As shown in Figures 8 and 11 the drum is provided with a perforated boss7 2 within which is slidablv keyed a bushing 73. Slidable through thisbushing. but keyed against relative rotation thereto, is the rod 70.Beyond the inner end of the boss 72 a collar 74 is fixed by means of aset screw 7 5 to the bushing 73 to fix its limit of movement toward theouter face of the drum 1. Bearing against the inner end of the bushing72 is a thrust ball bearing 76 of any suitable type and against the rearface of this thrust bearing is positioned a collar 77 threaded on therod 70. This collar has fixed thereto a handle 78 by which it may beturned. the

parts being so related that by pulling thehandle 78 forwardly the collar77 is turned in a direction to move the rod 70 axially to bring the head71 thereof toward the outer face of the drum. These parts are within thecircumferential outline of the drum so as not to project thei'ebeyond asthe chuck is rotated, and the side wall of the drum is discontinuous toform a large opening 19 through which access may be had to actuate thehandle 78. On the opposite side of the collar 77 the rod is of reduceddiameter and surrounding this reduced portion is a spring 79 bearing atone end on acollar 80 and at the other end against the inner wall 2 ofthe drum 1. This reduced extremity of the bar 70 passes through aperforation in this wall and is threaded at its end to receive abutmentnuts 82 which limit the possible movement of this rod in a dire tion tomove the head 71 away from the opposite end face of the drum, suchmovement being urged by the spring 79. The rod 70 passes loosely througha perforation 83 in the member 31 and its head rides in a counterboredportion 84 thereof, the parts being so proportioned that the head 72 maybear against the base of the counterbored portion but permit the desiredfloating movement of the member 31 relative to the drum before the head71 is brought up tightly tliereagainst. As the clamping mechanism hasits floating and pivotal connection to the drum eccentrically thereof,means is provided for counterbalancing the eccentric weight thereof whenthe chuck is in its stationary loading and unloading position so thatthis weight may have no effect in determining the clamped position ofthe work. For this purpose the member 31 may have a vert cal perforation85 therein in the lower portion of which is axially slidable a pin 86which may rest against an abutment screw 87 threaded in the end of thedrum 1 as more clearly shown in Figure 10. The clamping jaws are held upb a spring 870 positioned above the pin 86, t e lower end of the plug 88threaded in the upper end of the perforation 85 bearing on the upper endof this spring.

Means is also provided for supporting the outer end of the drum forrotation, this being in the nature -of a steady rest. As shown best inFigure 11, near the outer end of the drum 1 is a rib 90 having itsperiphery finished to form a journal portion hearing within a ring 91.The ring 91 is split as at 92 (see Figure (3) and the two ends may besprung apart by means of a pin 93 threaded in an opening in one end ofthe ring and having a reduced extremity 941 bearing in a socket in theother. The position of the pin 93 may be fixed by means of a locking pin95 also threaded in the socket and bearing on the head of the pin 93,the pin 95 being held in position by means of a set screw 90. The ring91 is fastened to a supporting frame member 98 by means of bolts 99passing through enlarged openings 100 in the frame member and threadedin the ring 91. These enlarged openings permit adjustment of the ring 91relative to the frame member and this adjustment may be effected atspated points about the circumference of the ring in order to cause thering to be accurately adjusted to bear on the bearing rib 90 of the drumthroughout its circumference. This isaccomplished by means of a seriesof threaded plugs 101 seated in radially arranged openings spaced aboutthe periphery of the frame member 98 and bearing at their inner ends onthe outer circumference of the ring 91'. These plugs may be fixed inadjusted position by means of set screws 102 passing through the framemember 98 at right angles to these plugs and bearing at their inner endsthereon. Other adjusting plugs 107 bear on shoulders 108 adjacent toopposite ends of the split ring 91. i

As shown best in Figures 6 and 7 the frame member 98 is fixed to thebody of the machine by clamp plates 103 held in position by bolts 104and may also be clamped by means of clamping bolts 105 about one of thetool-carrying bars 106 forming a part of the Fay lathe.-

\Vhen a crank shaft is to be machined the shaft should be adjustedlengthwise in order that the tools which are used to machine the centerbearing shall be correctly related ax- This gage block 110 has a pair ofoppositely all of these faces being in a common plane and being adaptedto be brought up against the outer face of the clamping mechanism. Thecrank shaft is placed in position, the tailstock spindle T of Figure 11being retracted and the spindle 10 being projectedby the spring 15 toits outer limit of motion.

In this position of the parts the throws A and B of the crank areoutward of the clamping mechanism. The tailstock is movedup to engagethe outer end of the shaft and the gage block is then placed-in positionbetween the crank throws as illus trated in Figure 15. moved toward theheadstock, the center 10 retracting until the faces 114, and 116 Thetailstock is then g bear against the clamping mechanism. The" toolcarriages 120 and 121 are so positioned relative to the clampingmechanism that they will take off equal portions of the checks of thecrank throws in this position of the parts. \Vhen the clamp has thusbeen adjusted to the proper axial position the gage block is removed, ahandle portion 118 being provided thereon so that it may be readilyhandled. The clamping awsare then engaged about the shaft, the rod 70being in its released position to permit the clamping mechanism to floatso that this mechanism may accommodate itself to the natural position ofthe shaft. These clamping elements are then brought into clampingrelation as above described, and then by pulling over the handle 78 theyare frictionally clamped against the outer end face of the drum torotate therewith. By th1s procedure the shaft is properly centered andarranged lengthwise properly so that the machining operation performedon the center bearing is accurately related to the axis and length ofthe shaft. A crank shaft of this description is shown detached in Figure2, the bearing which it is desired to machine when this chuck is beingused being indica ted at D.

Another form of mechanism particularly intended for use when machiningcam shafts is shown in detail in Figures 16 to 21. Referring to thesefigures, indicates the drum fixed at one end to the lathe spindle 3 andat its other end carrying the workclamping mechanism. In this form ofthe device the mechanism comprises'a clamping member 151 shown detachedin Figure 18 having a cut away portion forming an extension 152 to whichis pivoted a clamping jaw 153 (shown detached in Figure 17). The pivotpin 154 between the jaw and member passes through mating perforations155 and 156 in the clamping members and is a close fit therein. Themember 151 also has a perforation 157 counter-bored at 158 to receiveloosely the shank and head, respectively, of a pivot bolt 159. Thispivot bolt is pivoted closely in a key 160 mounted to slide in atransverse guideway 161 in the rear face of the member 151 and it alsopasses closely through a perforation in the end wall 162 of the drum 150and has a nut 163 threaded on its inner end. This permits the member 151to move bodily lengthwise of the key 160 and also permits it to pivotabout the )in 159 as an axis, this construction furnishing a floatingconnection for the member 151 to the end of the drum 150. The free endof the clamping jaw 153 may be urged about its pivot 151 toward themating clamping member. For this purpose a bolt is shown as pivoted at171 between the ears 172 on the member 151 and carries threaded on itsouter end a knurled knob 173 adapted to engage behind a pair of lugs 174projecting from the free end of the jaw 153, these lugs defining a slot175 between them in which the shank of the bolt 170 may lie. Theadjacent faces of the members 151 and 153 maybe notched out to conformsomewhat to the shape of the piece of work to be engaged thereby, thisbeing indicated more particularly in Figures 17, 18 and 19. Means areprovided for urging the free end of the clamping jaw toward clampingposition, this means, as shown, comprising a pin 176 slidable in aperforation 177 in the member 151' and urged outwardly by means of aspring 178 seated in this perforation and reacting against a plug 179threaded in the opposite end of the perforation 177. The outer end of.the pin 176 engages a face 180 formed on the jaw 153.

These clamping members 151 and 153 may be held against floating withrelation to the drum 150 and for this purpose the extension 152 of themember 151 is formed with a large perforation therethrough and the jawmember 153 is formed with a similar perforation 186 terminating in acounterbored portion 187, the openings 186 and 187 as shown beingsomewhat elongated to permit considerable movement of the clamping jaw153 relative to the locking member. This locking member comprises anaxially movable bar or rod 190 having a head 191 at its outer end seatedwithin the opening 187 in the jaw Its shank 192 extends loosely throughthe perforation 185 and through a sleeve 193 keyed in the drum in thesame manner as the locking rod .70 in the form of mechanism heretoforedescribed.

Against the inner end of this sleeve 193 is a ball thrust bearing 191and threaded on the shank 192 on the opposite side of this thrustbearing is a collar 195 in which is engaged the inner end of a handle196. By rocking this handle it is evident that the rod 190 may bereciprocated to bring its head into clamping engagement against the baseof the counterbored portion 187 and urge the jaw and member against theend face of the drum to prevent further floating of the clampingmechanism. This mechanism is released when the collar 195 is rocked inthe opposite direction, by means of a spring 197 seated in a socket 198in the opposite end of the locking rod 190 and bearing against a pin 199which engages against the inner wall of the opposite end portion 200 ofthe drum.

The outer end wall 162 of the drum is of the shape indicated best inFigure 21, having a perforation 201 therein through which the pivot 159extends and a depression 202 to receive the inner end of the pivot 154and its fastening nut 203, and having a perforation provided with a keyslot at 205 t slidably receive the sleeve 193.

' A further modification is shown in Figures 22 to 28. Referring tothese figures,

210 indicates the drum attached to the end of the spindle 3 and thisdrum carries on a pivotal floating connection similar to thosehereinbefore described a clamping member 211-. To this member is pivoteda jaw 212 on the pivot 213 which jaw may be urged toward the clampingmember by means of a threaded socket element 214 engaging the jaw andthreaded over an eye bolt 215 pivoted at 216 to the member 211. Themember 211 is rovided with a spring pressed counterbalance pin 217reacting agalnst an abutment 218 fixed to the drum as in the first formof mechanism described and the clamping mechanism may be fixed againstfloating by means of an axially movable headed rod 220 having a similaraction to that already described in connection with other forms ofchuck. In place of the head of this rod acting directly against a partof the clamping mechanism in this embodiment, additional frictional holdis effected by the use of a plurality of rings 221 and terbored portionand their inner diameters 222 interposed between the head of theclamping rod and the face of the counterbored ortion 223 in which thishead extends. The rings 221 as shown have an internal diameter closelyfitting the shank of the rod 220 and their outer circumferences areconsiderably smaller than the counterbored portion. The rings 222, onthe other hand, have their outer diameters a snug fit in thecounsomewhat greater than that of the shank of the clamping rod, theserings 221 and 222 being positioned alternately axially of the clampingrod. The rings 221, therefore, are held with the clamping rod during thefloating movement of the work-clamping mechanism, while the rings222.1nove with the clamping mechanism and relative to the clamping red,the two sets of rings overlapping each other. When the head of theclamping rod, however, is moved axially it presses all these ringstogether and against the base of the counterbored portion, thus takingadvantage of the frictional hold between the rings as well as thatagainst the base of the counterbored portion.

In this form of the device, also, the rear end of the 'clampingrod isshown as pass ing into a socket 225 on the inner end of the drum where apair of nuts 226 thereon furnish a stop to determine the outward limitof motion of the rod tending to release the clamping mechanism. The rodis normally urged to released position by means of a pin 227 seated inan axial opening therein and pressed outwardly against the end wall ofthe spindle 3 by means of a spring 228 positioned within this socket. Inthis form also the floating mounting of the member 211 is provided bythe use of a key 230 in which of the member 211which is provided with anenlarged perforationi233 to receive the pivot pin as shown in Figure 24.

Also, (see Figure 22), removable wear pieces 250 and 251 ma be fixed tothe clamping member, each or these wear pieces as shown having a shank252 and'253 which is made fast in a perforation in its respectiveclamping'element. A modification of this is shown in 'Fi ure 28 in whichthe wear piece 260 is use this being formed of a cylindrical bar whichfits in a mating socket 261 in the clamping element, this socket beingmore than hemi-cylindrical in cross sect1on so as to retain the wearpiece therein from removal except by movement parallel to its axis. Itmay be held from removal in this direction by means of a set screw 262passing through the clamping element and engaging it at its inner end.The end wall 270 oi the drum is somewhat similar to the outline shown inFigure 21 and has a perforation 271 to receive the pivot pm 231 and itssecuring nuts, a threaded opening 272 to receive the abutment plug 218,and a perforation 273 having a keyway" 274 to receive the locking rod.

Having thus described certain embodiments of this invention it should beevident to those skilled in the art. that certain changes andmodifications may be made therein without departing from its spirit orscope as defined by the appended claims.

I claim:

1. A device of the class described comprising a drum attachable at oneend to a machine spindle to rotate therewith, means for rotatablysupporting said'drum adjacent to its opposite end, said drum beinghollow to permitwork to extend axially therethrough and to be centeredrelative to said spindle,

means floating on said opposite end foiu.

and to be centered relative to said spindle,-

lneans floating on said opposite end for clamping work extending throughsaid drum, and means extendin and lying within said drum actuable to fixsaid clamping means to said opposite end and to release the same, saiddrum having an opening through its side through which said fixing andreleasing means is accessible.

3. A device of the class described comprising a rotatable support,work-clamping members floatingly carried by said support, and means forclamping said members against floating movement. I

4. A device of the class described comprising a drum attachable at oneend to a machine spindle, work-clamping mechanism fioatingly carried on.the opposite end of said drum and engageable with work extending intosaid drum in cooperative relation to said spindle, and means forclamping said mechanism against floating movement.

5. A device of the class described comprising a drum attachable at oneend to a machine spindle, work-clamping mechanism fioatingly carried onthe opposite end of said drum and engageable with work extending intosaid drum in cooperative relation to said spindle, a headed rod slidablcthrough said opposite end and freely through said mechanism, and meansfor movingsaid rod axially to clamp said mechanism against floatingmovement bet-ween said head and drum end.

6. A device of the class described comprising a drum attachable at oneend to a machine spindle, work-clamping mechanlsm fioatingly carried onthe opposite'end of said drum and engageable withwork extending intosaid drum in cooperative relation to said spindle, a headed rod slidablethrough said opposite end and freely through said mechanism, means for,moving said rod axially to clamp said mechanism against floatingmovement between said head and drum end, and means normally urging saidrod in the'opposite direction to release said mechanism.

7. A device of the class described comprising a rotatable drum,work-clamping mechanism floatingly carried by said drum, a headed rodhaving a close sliding fit in a perforation on said drum and a loosesliding fit in a crforation in said mechanisnn and means or urging saidrod axially to clamp said mechanism against said drum to hold saidmechanism from floating relative thereto.

8. A device of the class described comprising a hollow drum attachableat one end to a machine spindle, a work-clamping member having atransverse slide-way therein, a key slidable in said way, a pivotextending through said key and-the opposite end of said drum, awork-clamping jaw pivoted to said member, means to hold work arrangedaxially of said spindle and extending within "said drum clamped betweensaid jaw and member, and means actuable to clamp said member againstsaid opposite end preventing relative motion thereof.

9. A device of the class described comprising a drum attachable at oneend to a spindle to rotate therewith, a work-engaging member having atransverse slideway therein. a key slidable in said way. a'pivotextending through said key and the opposite end of said drum, a jawpivoted adjacent to one end of said member, saidjaw and memher beingpositioned to engage opposite sides of work extending into said drumaxially of said spindle, means .to draw said jaw toward said 'member toclamp the work, a member extending lengthwise through said drum andloosely through said member and having a head positioned outwardly ofsaid member, and means for moving said headed member axially to bringsaid head against said work-engaging member and hold said work-engaginmember frictionally against the end of said drum.

10. A device of the class described comprising a drum attachable at oneend to one end of said machine spindle to rotate axially therewith, saiddrum being hollow to permit work held in axial alinement with saidspindle to extend therethrough, a workclamping member having a pivotaland sliding connection with the opposite end of said drum, a clampingjaw pivoted to said member, means to draw the free. ,end of said jawtoward said member to clamp the Work therebetwcen, an element extendinglongitudinally through said drum and having a head outwardly of saidother end, and means within the drum for reciprocating said element tobring said head into position to hold said clamping member againstmovement relative to said drum and to release the same.

11. A device of the class described comprising a drum attachable at oneend to one end of a machine spindle to rotate axially therewith, saiddrum being hollow to permit work held in axial alinement with saidspindle to extend therethrough, a work-clamping member having a pivotaland sliding con nection with the opposite end of said drum, a clampingjaw pivoted to said member, means to draw the free end of said jawtoward said member to clamp the work therebetween, an element extendinglongitudinally through said drum and having a head outwardly of saidother end, and means within the drum for reciprocating said element tobring said head into position to hold said clamping member againstmovement relative to said drum and to release the same, said drum havingan opening therethrough through which-said reciprocating means isaccessible for manual operation.

12. A device of the class described comprising a rotatable drum.work-clamping mechanism floatingly carried by said drum. said drumhaving a perforation, a headed rod closely fitting said perforation andslidable axially therethrongh,a socket in said mechanism having a largerperforation through its base through which said rod loosely passes,rings fitting closely in said socket. the internal diameters of saidrings being larger than said rod, other rings arranged in said socketalternately to said first mentioned rings, said other rings closelyfitting said rod and of smaller internal diameter than said socket, butoverlapping said first mentioned rings, and means for moving said rodaxially to bring its head against said rings to clamp them against eachother and to the base of said socket and said member against said drumto prevent fioating movement thereof.

13. A device of the class described comprising a rotatable drum, awork-clamping member floatingly pivoted adjacent one end to one face ofsaid drum, a clamping jaw having one end pivoted to said member, meansto clamp work between said jaw and member, means for counterbalancingthe weight of said member and jaw about said floating pivot in oneangular position of said drum, and means to clamp said member to saiddrum to prevent relative floating thereof.

14. A device of the class described comprising a rotatable drum, awork-clamping member floatingly pivoted adjacentone end to one face ofsaid drum, a clamping jaw having one end pivoted to said member, meansto clamp work between said jaw and member, means for counterbalancingthe weight of said member and jaw about said floating pivot in oneangular position of said drum, said means comprising an abutmentextending outwardly from said drum, a plunger slidable in a socket insaid member and engageable with said abutment, and a spring in saidsocket back of said plunger.

15. A gage for determining the axial position of a crank shaft relativeto a chuck which comprises a block having inclined opposed facesengageable between the checks of a crank portion of said shaft, and aportion spaced from said faces and engageable with a face of the chuck.

16. A gage for determining the axial position of a crank shaft relativeto a chuck which comprises a block having inclined opposed facesengageable between the cheeks of a crank portion of said shaft, and aplurality of surfaces engageable with a face of the chuck at oppositesides of said shaft.

17. A gage for determining the axial position of a crank shaft relativeto a chuck which comprises a block having inclined opposed facesengageable between the cheeks of a crankportion of said shaft, aplurality of surfaces engageable with a face of the chuck at oppositesides of said shaft, and a face engageable with another portion of theshaft.

18. A gage for determining the axial position of a crank shaft relativeto a chuck which comprises a block having inclined opposed facesengageable between the checks of a crank portion of said shaft, andthree faces arranged about one of said inclined faces engageable withthe face of the chuck.

19. A gage for determining the axial position of a crank shaft relativeto a chuck which comprises a block having inclined opposed facesengageable between the cheeks of a crank portion of said shaft, threefaces arranged about one of said inclined faces engageable with the faceof the chuck, and a face engageable with another portion of the shaft. 1

20. In combination with a chuck havingmcans for clamping acrank shaftadjacent to a crank throw, of a member engageable between the cheeks ofa crank and against said chuck to fix 'an axial position of said shaftrelative to said chuck.

In testimony whereof I have afiixed, my signature.

JOHN E. LOVELY.

